Field of the Invention
The present invention relates to an optical member and an image display device having the optical member.
Background Art
Demand for a system in which data is input by handwriting on a display of an image display device by using an electronic pen or the like has increased in recent years. Patent Literature 1 discloses a transparent sheet on which a dot pattern made of transparent ink containing a liquid crystal material having a cholesteric structure selectively reflecting infrared rays is printed on a transparent substrate. This transparent sheet is attached to a display device and can be used for the above-described system in combination with the electronic pen including an infrared sensor for detecting reflected light from the dot pattern and an infrared irradiation portion.
Patent Literature 1: Japanese Patent Laid-Open No. 2008-165385
Patent Literature 2: Japanese Patent Laid-Open No. 2011-154215